Mushrooms: “Nature’s Greatest Decomposers”

Posted on April 18, 2019

An Indigenous-led organization in New Mexico is using fungus in an attempt to remove chemicals from soil.

At the Española Healing Foods Oasis in Española, New Mexico, Pueblo dryland farming techniques are on display in a downtown public park. The garden, designed and planted by the Indigenous-led organization Tewa Women United, demonstrates how food and medicine can be grown in an environment that receives just 11 inches of rain per year. And at a nearby community garden, which the organization helped operate in the past, Pueblo members and locals grow fruit and vegetables.

The garden projects are part of the organization’s efforts to grow foods and herbs for people in the Eight Northern Indian Pueblos, as well as locals in the wider Española Valley, using traditional methods. But there’s a problem: The soils at these gardens are being exposed to contaminants. Tewa Women United hopes oyster mushrooms will clean them up.

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At the community garden, a 2015 study found levels of contaminants high enough to threaten human health. Similarly toxic levels of these or other contaminants were not found at the Foods Oasis, though petroleum from a nearby parking lot percolates into the soil there when it rains. So far, tests of petroleum at that site have shown levels within state standards, but Beata Tsosie-Peña of the Santa Clara Pueblo and program coordinator at Tewa Women United said that the organization’s standards are stricter than the state’s. People from local Pueblos consume food and herbs from the Oasis, she said.

Tsosie-Peña added that community elders experience disease, illness, and miscarriage as a result of pollution in the area.

“We’re not disconnected from our lifeways and rootedness in our land base, tradition, and culture,” she said, adding that by “living off the land and having that intimate relationship ... does put us at risk for more exposure to contaminants.”

The problem is bigger than soil toxins at these gardens. At nearby Los Alamos National Laboratory, hexavalent chromium, a heavy metal and known carcinogen, is seeping into the water supply.

Hexavalent chromium is a byproduct of the lab’s work to design nuclear weapons. The Department of Energy lab at Los Alamos was established in 1943 as part of the Manhattan Project. This location was selected for its isolation. Yet Pueblo people lived there at the time and still inhabit the land.

The risk of toxic exposure in their community has led Tewa Women United to explore methods to clean up the soils. They’ve begun by experimenting with mushrooms at the Healing Foods Oasis and the nearby community garden site.

Mycologist Peter McCoy explains that in a process called mycoremediation, mushrooms have the ability to remove chemicals from soil—and heavy metals from water—through their mycelium.

“They’re sort of nature’s greatest decomposers, disassemblers, by far better than and more powerful than bacteria, animals, and plants,” McCoy said. “They break all kinds of stuff down.”

Mushrooms have helped remove petroleum from soil everywhere from Orleans, California, where they cleaned up a small motor-oil-and-diesel-fuel spill at a community center, to the Ecuadorian Amazon, where they’re being used to clean up the largest land-based oil spill in history.

In April 2018, Tewa Women United buried bricks inoculated with oyster mushroom mycelium at the Foods Oasis and community garden.

While the organization doesn’t have funding for formal scientific testing, it is seeking out money to run pilot studies on its own. They plan to check the soil later this spring to see whether the mycelium has been spreading underneath the surface.

“It has been proven already what the mycelium can do,” Tsosie-Peña says, referring to other examples around the world. “So we are moving forward with inoculating all our garden sites as a proactive measure … but recognize the need to also have scientific backing [provided by] before and after sampling to gain support for widespread implementation.”

The organization has also asked Los Alamos to explore mycroremediation as a method to clean up the hexavalent chromium on its property. Communities for Clean Water, a coalition of environmental and indigenous advocacy organizations including Tewa Women United, advocated in public testimony at a hearing in November that the laboratory use mycoremediation to clean up the heavy metals. The hearing was for a groundwater cleanup permit originally issued in 2015. That permit was issued to Los Alamos by the New Mexico Environment Department without a public hearing, but after the coalition pushed back, it granted the one in November. But in March, the hearing officer’s report determined the permit would continue as originally issued in 2015, as “current water treatment methods are sufficient to meet and exceed the applicable groundwater and drinking water standards.”

Tsosie-Peña said the decision was disappointing because most of the recommendations—including the use of mycoremediation—that came from more than six hours of public comments were not reflected in the report.

The New Mexico Environment Department Ground Water Quality Bureau says it can’t consider mycoremediation in the proceedings related to this particular discharge permit. According to Bureau Chief Michelle Hunter, the activity that Los Alamos completes with this permit is just an intermediate cleanup action in which the lab is authorized to treat and release groundwater on its property.

Hunter explained that the remediation process will start after “all these interim measures have been implemented” and that a different bureau—the Hazardous Waste Bureau—will handle that process.

At that point, Los Alamos and the Hazardous Waste Bureau will choose the remediation technology.

Los Alamos has piloted a couple of remediation strategies, she said, including one that injected molasses into the water and another that used sodium dithionite. If the coalition wants mycoremediation to be considered, they’ll have to advocate for it to get evaluated in the remediation process that the Hazardous Waste Bureau will lead.

For now, Tewa Women United is doing what it can to clean up soils at the community gardens and Foods Oasis and plans to bury more mushroom-inoculated bricks in the community garden sites soon.

Tsosie-Peña said her organization is also working with the Communities for Clean Water Coalition to secure resources and collaborators to implement two pilot projects. One is on Los Alamos property, and another is in local communities downwind from the lab.

She said that while the coalition didn’t get their preferred outcome with the groundwater permit, she hopes they can advocate for mycoremediation in other, separate, work they are doing with Los Alamos on stormwater permitting.

“I think the mainstream view is that these places have been lost to us because they’re contaminated,” Tsosie-Peña said. “But to me, it’s like you wouldn’t just abandon your sick grandmother in the hospital to suffer alone.

“That’s how we feel about these places. They’re sick. They need healing. They need our love and attention more than ever.”